(66 days)
The MRII Cranial Drill and Accessories are intended to provide access through the skull for ventriculostomy or other neurological procedures, such as biopsy or catheter placement, in or near an MR scanner of 3T maximum strength. The MRII Cranial Drill and Accessories are intended to be used only when the scanner is not performing a scan. The MRII Cranial Drill is intended for single use only.
The MRII Cranial Drill and accessories is composed of the MR Compatible Hand Drill and Drill Bit Kits, packaged separately and found substantially equivalent in K 122456. The packaging is identical to that of the predicate device. The MRII Cranial Drill is wrapped in CSR and then sealed in a Tyvek pouch. The Drill Bit Kits are packaged in a sealed tray within a sealed Tyvek pouch.
The provided document, a 510(k) summary for the MRII Cranial Drill and Accessories, details performance data and a risk analysis to demonstrate substantial equivalence to a predicate device. It primarily focuses on the device's mechanical performance and safety within an MRI environment, rather than the performance of an AI algorithm or a diagnostic tool. Therefore, many of the requested fields related to AI performance, such as sample size for test sets, data provenance, number of experts for ground truth, adjudication method, MRMC studies, standalone performance with humans-in-the-loop, and training set information are not applicable to this device and document.
Here's a breakdown of the available information:
1. Table of Acceptance Criteria and Reported Device Performance
| Test | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Drilling Efficiency, Smooth Operation, and Vibration during Drilling | Drilling Efficiency: Drill through simulated material in under 1 minute. Smooth Operation and Vibration During Drilling: User evaluation score of 3.0 (scale of 1.0 - 5.0) or higher. | All modified MRI Hand Drills met the acceptance criteria. All Hand Drills were able to drill through the simulated material in under a minute and received user evaluation scores greater than 3.0 for both smooth operation and vibration during drilling. This was substantially equivalent to the predicate Hand Drill. |
| Drill Bit Retention under Axial Loading, Drill Bit Loading, and Handling with Wet Gloves | Drill Bit Retention Under Axial Loading: 0 mm slippage under a 5.0 lbf minimum force. Drill Bit Loading, Wet Glove Usage: A user evaluation score of 3.0 (scale of 1.0 - 5.0) or higher. | All modified MRI Hand Drills met the acceptance criteria. None of the modified Hand Drills had any slippage when a minimum axial load of 5.0 lbf was applied in both tension and compression directions. The Drill Bit Loading and Wet Glove usage requirements both scored higher than 3.0 for all modified Hand Drills tested. This was substantially equivalent to the predicate Hand Drill. |
| Drill Bit Retention under Torque Loading, Drill Bit Loading, and Handling with Wet Gloves | Drill Bit Retention Under Torque: No movement of the Drill Bit inside the Chuck Housing, when a Torque is applied to the Drill Bit. Drill Bit Loading, Wet Glove Usage: A user evaluation score of 3.0 (scale of 1.0 - 5.0) or higher. | All modified MRI Hand Drills met the acceptance criteria. None of the modified Hand Drills had any slippage when a minimum torque 10 in-lbf was applied to the Drill Bits. The Drill Bit Loading and Wet Glove usage requirements both scored higher than 3.0 for all modified Hand Drills tested. This was substantially equivalent to the predicate Hand Drill. |
| MRI Hand Drill and Drill Bit Run-out Testing (new comparative test) | The modified Hand Drill shows a reduction in the amount of Run out in the Drill and Drill Bit. | All modified Hand Drills had approximately a 50% reduction in the amount of run-out (unwanted movement). This improvement does not change the use, safety or effectiveness of the Hand Drill. |
| MRI Hand Drill Shaft Deflection Test (new comparative test) | The modified MRI Hand Drills show a reduction in the amount of deflection in the shaft when a side load is applied to the Chuck assembly. | All modified MRI Hand Drills had a reduction in the amount of deflection by approximately 60%, compared to the PEEK shafts of the predicate Hand Drill. This improvement does not change the use, safety or effectiveness of the Hand Drill. |
| Chuck Housing Lock Washer Break Force Test (new test) | The Lock Washers shall have a minimum break force of 5 lbf. | All modified Hand Drills had a Lock Washer break force greater than 5.0 lbf. Predicate Hand Drills have not undergone this test, since they do not have a Lock Washer feature. This modification does not change the use, safety or effectiveness of the Hand Drill. |
| Chuck Tightening Torque vs. Chuck Insert Slip Torque (new comparative test) | No explicit numerical acceptance criteria is stated, but the goal is for the Chuck Insert not to slip at any tightening torque level. | The modified Hand Drill design did not slip at any level of Chuck tightening torque. The predicate Hand Drill Chuck Insert slip torque is approximately equal to the Chuck Housing's tightening torque. The user no longer has to tighten the chuck on the modified Hand Drill beyond what it takes to hold the drill bit. This modification does not change the use, safety or effectiveness. |
2. Sample size used for the test set and the data provenance
- Test Set Sample Size: The document does not specify exact numerical sample sizes for each test in terms of individual devices. It generally refers to "All modified MRI Hand Drills" or "Each Chuck/Shaft sub-assembly." For certain tests like "Drilling Efficiency," it mentions using 3.2, 4.5, and 6.0 mm Drill bits with "each Hand Drill Tested," implying multiple permutations.
- Data Provenance: The data is generated from in-house design verification testing conducted by the company (MRI Interventions, Inc.). This is prospective data from controlled experiments. The country of origin is not explicitly stated but can be inferred as the United States, given the FDA submission.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Not Applicable. This is a mechanical device performance study, not a medical imaging or diagnostic study requiring expert ground truth for interpretation. "User evaluation scores" are mentioned for "Smooth Operation and Vibration During Drilling," "Drill Bit Loading," and "Wet Glove usage," which implies subjective assessment by individuals, but their number and specific qualifications are not detailed beyond being users.
4. Adjudication method for the test set
- Not Applicable. As there is no expert consensus on ground truth, no adjudication method is relevant.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
- Not Applicable. This is not an AI-powered diagnostic device, so an MRMC study comparing human readers with and without AI assistance is irrelevant.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Not Applicable. This device does not involve an algorithm with standalone performance.
7. The type of ground truth used
- The "ground truth" for this device's performance is based on engineering specifications and measurable physical properties. For example, "0 mm slippage" for axial loading, "under 1 minute" for drilling efficiency, specific force and torque values, and reduction percentages for run-out and deflection. Some aspects involve "user evaluation scores" for subjective qualities like smooth operation and ease of handling.
8. The sample size for the training set
- Not Applicable. This is not an AI/machine learning device, so there is no training set. Design validation is based on physical testing and risk analysis.
9. How the ground truth for the training set was established
- Not Applicable. No training set exists.
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Image /page/0/Picture/1 description: The image shows the seal of the Department of Health & Human Services - USA. The seal features a stylized eagle with its wings spread, and the words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" are arranged in a circular pattern around the eagle. The eagle is depicted in a simple, graphic style, with bold lines and a sense of movement. The overall design is clean and professional, reflecting the department's role in public health and human services.
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
March 26, 2016
MRI Interventions, Inc. Mr. Peter Piferi Chief Operating Officer 5 Musick Irvine, California 92618
Re: K160129
Trade/Device Name: MRII Cranial Drill and Accessories Regulation Number: 21 CFR 882.4300 Regulation Name: Manual Cranial Drills, Burrs, Trephines, and Their Accessories Regulatory Class: Class II Product Code: HBG Dated: February 25, 2016 Received: February 25, 2016
Dear Mr. Peter Piferi:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices. good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you; however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical devicerelated adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
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If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to
http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely yours,
Carlos L. Pena -SD/A
Carlos L. Peña, PhD, MS Director Division of Neurological and Physical Medicine Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K160129
Device Name MRII Cranial Drill and Accessories
Indications for Use (Describe)
The MRII Cranial Drill and Accessories are intended to provide access through the skull for ventriculostomy or other neurological procedures, such as biopsy or catheter placement, in or near an MR scanner of 3T maximum strength. The MRII Cranial Drill and Accessories are intended to be used only when the scanner is not performing a scan. The MRII Cranial Drill is intended for single use only.
Type of Use (Select one or both, as applicable)
| ☑ Prescription Use (Part 21 CFR 801 Subpart D) |
|---|
| ☐ Over-The-Counter Use (21 CFR 801 Subpart C) |
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510(k) Summary
This 510(k) summary is being submitted in accordance with the requirements of 21 CFR Part 807.92 for the MRII Cranial Drill and Accessories.
Company Making the Submission: 1.
| Name of Owner: | MRI Interventions, Inc. |
|---|---|
| Address: | 5 MusickIrvine, CA 92618 |
| Telephone: | 949-900-6833 |
| Fax: | 949-900-6834 |
| Contact: | Peter Piferi |
| E-mail: | ppiferi@mriinterventions.com |
2. Date Prepared:
January 12th, 2016
Device Name: 3.
| Common Name: | Manual Drill |
|---|---|
| Proprietary Name: | MRII Cranial Drill andAccessories |
| Classification: | II |
| Regulation Number: | 21CFR 882.4300 |
| Product Code: | HBG |
4. Predicate Device:
MRII Cranial Drill and Accessories, K122456 SmartTwist MRII Hand Drill, SmartTip MRII Drill Bit Kit, 4.5mm, 6.0mm, K151536
5. Device Description:
The MRII Cranial Drill and accessories is composed of the MR Compatible Hand Drill and Drill Bit Kits, packaged separately and found substantially equivalent in K 122456. The packaging is identical to that of the predicate device. The MRII Cranial Drill is wrapped in CSR and then sealed in a Tyvek pouch. The Drill Bit Kits are packaged in a sealed tray within a sealed Tyvek pouch.
6. Indications for Use
The MRII Cranial Drill and Accessories are intended to provide access through the skull for ventriculostomy or other neurological procedures, such as biopsy or
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catheter placement, in or near an MR scanner of 3T maximum strength. The MRII Cranial Drill and Accessories are intended to be used only when the scanner is not performing a scan. The MRII Cranial Drill is intended for single use only.
7. Summary of the Technological Characteristics of the Device Compared to the Predicate Device:
Modifications of the predicate MRII Cranial Drill and accessories are:
a) Changing the drill shaft material from PEEK to anodized aluminum
b) Changing the drill chuck housing material from PEEK to Delrin and adding a locking pin and slot
c) Shortening the slots on the chuck insert
d) Adding a shoulder feature to the drill chuck housing
e) Changing the shaft coupler material from PEEK to Delrin and adding a shoulder feature
f) Adding a lock washer to the back of the chuck housing
g) Adding a PTFE spacer between the pinion gear and drill housing
h) Modifying the proximal end of the 3.2-mm Drill Bit from a round shank with one flat to a round shank with three flats. This is an identical design that was reviewed and cleared under K151536.
The MRII Cranial Drill and 3.2mm Drill Bit shank modifications are part of continuous product improvement efforts. These minor changes make insertion of the Drill Bits and tightening of the Drill Chuck easier. These modifications will also allow the drill to rotate smoother with less run out.
| MRII Hand Drill andAccessories with minor designmodifications | Predicate DeviceMRII Hand Drill andAccessoriesK151536 | |
|---|---|---|
| Classification | 21 CFR 882.4300 | 21 CFR 882.4300 |
| Product Code | HBG | HBG |
| Intended Use | The MRII Cranial Drill andaccessories are intended toprovide access through the skullfor ventriculostomy or otherneurological procedures, suchas biopsy or catheter placement,in or near an MR scanner of 3Tmaximum strength. The MRIICranial Drill and accessories areintended to be used only whenthe scanner is not performing ascan. The MRII Cranial Drill isintended for single use only. | The MRII Cranial Drill andaccessories are intended toprovide access through the skullfor ventriculostomy or otherneurological procedures, suchas biopsy or catheter placement,in or near an MR scanner of 3Tmaximum strength. The MRIICranial Drill and accessories areintended to be used only whenthe scanner is not performing ascan. The MRII Cranial Drill isintended for single use only |
| Environment | OR or MRI Suite | OR or MRI Suite |
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| Sterilization | EO 10^-6 SAL | EO 10^-6 SAL |
|---|---|---|
| Hand Drill Shaft(non patient contacting, minor change to reduce run out, performs same function) | O.D: .245 inLength: 3.97 inMaterial: Anodized Al 6061 | O.D: .240 inLength: 3.80 inMaterial: PEEK |
| Washer(non patient contacting, minor change to capture shaft coupler) | I.D: .435 inO.D: .625 inThickness: .031 inMaterial: Nylon | N/A |
| Gear Housing Inner Lip Depth(minor dimension change to reduce play) | .060 in | .090 in |
| Dowel Pin(non patient contacting, minor change to prevent slipping) | O.D: .063 inLength: .313 inMaterial: 316 SS | N/A |
| Chuck Insert (minor dimension change to improve drill bit engagement) | Tri-Slot Length: .525 inCross Pin Hole Dia: .063 in | Tri-Slot Length: .820 inCross Pin Hole Dia: N/A |
| Drill Shaft Coupler(non patient contacting, minor dimensional changes and to accept pin and washer) | O.D: .468 inLength: 1.12 inCross Pin Slot; Dia: .078 in, Length: .273Lock Washer Step; Dia: .425 in, Length .506 inDrill Shaft Pilot Hole; Dia: .246 in, Depth: .225 in Material: Delrin | O.D: .500 inLength: .90 inCross Pin Slot; N/ALock Washer Step; N/ADrill Shaft Pilot Hole; N/AMaterial: PEEK |
| Drill Chuck Housing(non patient contacting, minor dimensional changes to improve assembly, accept washer and improve ergonomics) | Length: 1.57 inLock Washer Seat; Dia: .642 in, Depth: .040Shaft Coupler Pilot Hole; Dia: .469 in, Depth .66 inMaterial: Delrin | Length: 1.16 inLock Washer Seat: N/AShaft Coupler Pilot Hole: Dia: .547 in, Depth .25 inMaterial: PEEK |
| Shim(minor change to reduce play and friction) | I.D: .25 inO.D: .375 inThickness: .030 inMaterial: Teflon | N/A |
| Drill Bit Included with Drill | No | No |
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| Drill Bit Sizes(proximal shankfeature, minor changeto improveengagement) | 3.2 mm (Tri Flat)4.5 mm (Tri Flat)6.0 mm (Tri Flat) | 3.2 mm (Single Flat)4.5 mm (Tri Flat)6.0 mm (Tri Flat) |
|---|---|---|
| Drill Bit Material | 316L SST | 316L SST |
| Adjustable DepthGuard | Yes | Yes |
| Packaging | Drill: Sterile, CSR Wrap inTyvek Peel PouchKit: Sterile, inside tray withTyvek Lid and external TyvekPouch | Drill: Sterile, CSR Wrap inTyvek Peel PouchKit: Sterile, inside tray withTyvek Lid and external TyvekPouch |
The modifications to the MRII Cranial drill and 3.2mm Drill Kit is substantially equivalent in intended use, technological characteristics and principles of operation to the predicate MRII Cranial Drill. Thus, the MRII Cranial Drill and 3.2mm Drill Kit modifications are substantially equivalent to the predicate.
8. Performance Data:
The modifications of the MRII Cranial Drill and 3.2mm Drill Kit were conducted in conformance with the company's design control procedures. Design inputs provided the requirements for the respective product specifications. Design Verification was performed relative to these specifications with acceptable results. Risk analysis was performed with mitigation of all identified risks to acceptable levels. The tests and risk analysis demonstrated that the modified MRII Cranial Drill and 3.2mm Drill Kit functions as intended and is substantially equivalent to the legally marketed MRII Cranial Drill and accessories.
Verification Testing Performance Summary Modified MRI Hand Drill (K160129) Compared to the Predicate MRI Hand Drill (K122456, K151536)
| Testing per VPR-0111 Rev A. | |||
|---|---|---|---|
| Test | Test Method Summary | Results | |
|---|---|---|---|
| Drilling Efficiency, SmoothOperation, and Vibrationduring Drilling | Purpose: To evaluate theDrilling Efficiency, smoothoperation, and vibrationduring drilling, of the MRIHand Drill. | All modified MRI HandDrills met the acceptancecriteria. All Hand Drills wereable to drill through thesimulated material in under aminute and received userevaluation scores greater than3.0 for both smooth operationand vibration during drilling.This was substantiallyequivalent to the predicate | |
| Set-up: A block of sawboneswith a hardness of 65D wasused as the simulated skullmaterial. Simulated scalpmaterial was placed on top of | |||
| the Sawbones block. Thesample was clamped with atable vice, and placed on aweight scale. The Hand Drillswere used to drill holesthrough the simulationmaterial, using a drill speedof 1 handle turn per second,for each trial. 3.2, 4.5, and6.0 mm Drill bits were usedwith each Hand Drill Tested.Acceptance Criteria:Drilling Efficiency: Drillthrough simulated material inunder 1 minute. SmoothOperation and VibrationDuring Drilling: Userevaluation score of 3.0 (scaleof 1.0 - 5.0) or higher. | Hand Drill. | ||
| Drill Bit Retention underAxial Loading, Drill BitLoading, and Handling withWet Gloves | Purpose: To determine howwell the Hand Drills' Chuckgrips the Drill Bit, when anaxial loading is applied to theDrill Bit.Set-up: A Drill Bit wasattached to the MRI HandDrills, using wet gloves; TheDrill Bit was not fully seatedinside the Chuck, to allow forit to slip in compression.Then, the Drill was clampedto the table, using a table viceand clamping directly on theDrill, such that the Drill Bithangs freely. A Force Gaugewas then attached to the DrillBit, to administer a 5.0 lbfminimum compression load,and see if Drill Bit would slipfurther into the Chuck.Afterwards, The Force Gaugewas used to pull on the DrillBit, to administer a 5.0 lbfminimum force, and see if theDrill Bit would slip out of the | All modified MRI HandDrills met the acceptancecriteria. None of the modifiedHand Drills had any slippagewhen a minimum axial loadof 5.0 lbf was applied in bothtension and compressiondirections. The Drill BitLoading and Wet Gloveusage requirements bothscored higher than 3.0 for allmodified Hand Drills tested.This was substantiallyequivalent to the predicateHand Drill. | |
| Drill Bit Retention underTorque Loading, Drill BitLoading, and Handling withWet Gloves | Chuck in tension. Markswere made on the drill bits tomeasure the slippage basedon the before and aftermeasurements. This test wasperformed for the 3.2 and 4.5mm Drill Bits with the Tri-flat geometry.Acceptance Criteria: DrillBit Retention Under AxialLoading: 0 mm slippageunder a 5.0 lbf minimumforce. Drill Bit Loading, WetGlove Usage: a userevaluation score of 3.0 (scaleof 1.0 - 5.0) or higher. | All modified MRI HandDrills met the acceptancecriteria. None of the modifiedHand Drills had any slippagewhen a minimum torque 10in-lbf was applied to the DrillBits. The Drill Bit Loadingand Wet Glove usagerequirements both scoredhigher than 3.0 for allmodified Hand Drills tested.This was substantiallyequivalent to the predicateHand Drill. | |
| Purpose: To determine howwell the Hand Drills' Chuckgrips the Drill Bit, whenTorque is applied to the DrillBit.Set-up: A Drill Bit wasattached to each MRI HandDrill, using wet gloves. Then,the Drills were clamped tothe table, using a table vice.A Torque Gauge wasattached to the opposite endof the drill bit. A Torque wasthen applied to the drill, tosee if there was anynoticeable slip. Alignmentmarks where made of theDrill Bit and Chuck Housing,to see if there was anymisalignment after applyingthe torque. This test wasperformed for the 3.2 and the4.5 mm Drill Bits with Tri-flat geometry.Acceptance Criteria: DrillBit Retention Under Torque:No movement of the Drill Bitinside the Chuck Housing, | |||
| MRI Hand Drill and Drill BitRun-out Testing (newcomparative test) | when a Torque is applied tothe Drill Bit. Drill BitLoading, Wet Glove Usage: auser evaluation score of 3.0(scale of 1.0 - 5.0) or higher.Purpose: To measure theamount of Run-out in theHand Drill/Drill Bitassembly, when the drill isrotating.Set-up: The Hand Drill Bodywas clamped in a table vice,such that the Hand Drillcould still spin freely. A DrillBit was attached to the Drill.A deflection gauge wasplaced at different point onthe drill; on the ShaftCoupler, The ChuckHousing, on the Drill Bit nearthe Chuck Housing. TheDrills were then turned, tosee how much "wobble" wasmeasured at each point. Thiswas repeated forAcceptance Criteria: Themodified Hand Drill shows areduction in the amount ofRun out in the Drill and DrillBit. | All modified Hand Drills hadapproximately a 50%reduction in the amount ofrun-out (unwantedmovement). Thisimprovement does notchange the use, safety oreffectiveness of the HandDrill. | |
| MRI Hand Drill ShaftDeflection Test (newcomparative test) | Purpose: To measure theamount of deflection in theShaft, when a side load isapplied to the ChuckHousing.Set-up: The hand Drill Bodyis clamped into a table vice.A force gauge is used toapply a 5 lbf side loadingonto the Chuck Housing. Theamount of deflection of theHousing is measured with adeflection gauge. | All modified MRI HandDrills had a reduction in theamount of deflection byapproximately 60%,compared to the PEEK shaftsof the predicate Hand Drill.This improvement does notchange the use, safety oreffectiveness of the HandDrill. | |
| Acceptance Criteria: Themodified MRI Hand Drillsshow a reduction in theamount of deflection in theshaft when a side load isapplied to the Chuckassembly. | |||
| Chuck Housing Lock WasherBreak Force Test (new test;this test was not performedon predicate devices, sincepredicates does not have thisfeature) | Purpose: To characterize thestrength of the Loctite bondbetween the Chuck Housingand Lock Washer.Set-up: Chucks wereloosened fully on HandDrills. Drill Bodies wereclamped to a Table Vice. Aclamp was attached to theChuck Housing, which wasconnected to the ForceGauge. The Force gauge wasused to pull on the ChuckHousing axially, until thebond between the LockWasher and Chuck Housingbroke. The break force wasthen measured.Acceptance Criteria: TheLock Washers shall have aminimum break force of 5lbf. | All modified Hand Drills hada Lock Washer break forcegreater than 5.0 lbf. PredicateHand Drills have notundergone this test, sincethey do not have a LockWasher feature. Thismodification does not changethe use, safety oreffectiveness of the HandDrill. | |
| Chuck Tightening Torque vs.Chuck Insert Slip Torque(new comparative testdeveloped when the NewPinned Chuck Insert designwas introduced) | Purpose: The Chuck Insert'sslip torque was measured atdifferent tightening torquesof the Chuck Housing. Thiswas done to see how well thenew cross pin feature insidethe Insert prevents the ChuckInsert from spinning insidethe Chuck Housing.Set-up: Each Chuck/Shaftsub-assembly was removedfrom each Hand Drill GearHousing. A Drill Bit was | The modified Hand Drilldesign did not slip at anylevel of Chuck tighteningtorque. The predicate HandDrill Chuck Insert slip torqueis approximately equal to theChuck Housing's tighteningtorque. The user no longerhas to tighten the chuck onthe modified Hand Drillbeyond what it takes to holdthe drill bit. Thismodification does not changethe use, safety or |
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Summary of Risk Analysis
An FMEA was performed for the Hand Drill with modifications (FMEA-0063). The summary of the risk analysis is provided below. The following table is used for the O,S, and D rankings.
| Occurrence(probability) | Detection (Chance ofdetecting failure) | Severity (ClinicalEffect) | Non-HazardousSeverity |
|---|---|---|---|
| 1 - Low (1 in400) | 1 - Detection is certain | 1 - Unnoticeable touser. No effect onperformance. | 1 - No noticeabledelay/ nodissatisfaction |
| 3 - Infrequent (1in 200) | 2 – High probability ofdetection | 3 - Minor impact topatient. Minimalimpact to patientbaseline status | 3 - Minor delay/ slightdissatisfaction |
| 5 - Periodic (1 in100) | 4 - Detectionprobability is moderate | 5 - Patient injury notrequiring treatment.Alteration of patient'sclinical baselinestatus | 5 - Noticeable delay/statement ofdissatisfaction likely |
| 7 - High (1 in 50) | 6 - Detectionprobability is low | 7 - Reversible patientinjury. Alteration ofpatient's clinicalbaseline statusrequiring treatment | 7 - Prolonged delay/dissatisfactioncommunicated clearly |
| 10 - Very High(1 in 25) | 8 – Slight probability ofdetection | 8 – Irreversiblepatient injury | 8 - Extensive delay /extremedissatisfaction |
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| 10 - Detection almost | 10 - Death | 10 - Procedure |
|---|---|---|
| impossible | discontinued |
There were no items with residual RPN above 40. The highest severities (9) were for susceptibility to magnetic force or torque, as that could cause either loss of control or could cause the MRI Drill to be pulled into the scanner at high speed. However, this occurrence is essentially zero because the Drill is designed with non-ferromagnetic components. There are two cross-pins that are made out of 316L Stainless Steel. 316L has very low magnetic susceptibility, and the mass of the stainless steel pins is insignificant compared to the overall mass of the Hand Drill. The same 316L SST Pin is used in the predicate Hand Drill. Therefore, this risk is identical to the predicate Hand Drill.
The modified MRI Drill Shaft is also made out of anodized 6061 Aluminum. This modification to the Hand Drill did not increase any of the RPN's from the risk analysis performed on the predicate device.
The aluminum shaft has extremely low magnetic susceptibility (much lower than 316L SST), so it is unaffected by magnetic fields from 1.5T - 3.0T. So, the risk remained the same as the predicate Hand Drill.
The only new failure mode was the lock washer breaking off from the Chuck Housing. However, this has no clinical effect, and the occurrence is 1. The lock washer provides a benefit to the user since it prevents the Chuck Housing from falling off when the user loosens it. So the benefit of having the washer far outweighs the very minimal risk.
The modified Hand Drill also lowers the occurrence of two failure modes.
The Collet Jaws deforming during tightening the Chuck is now 1 (predicate device was 2), which lowers the RPN from 8 to 4.
The Chuck Housing does not have a good gripping surface for User to tighten adequately is now 1 (predicate device was 3), which lowers the RPN from 24 to 8.
All material changes from the predicate device are non patient contacting and do not provide any additional risk. The modified Hand Drill poses no additional challenge to sterilization over the predicate Hand Drill and therefore does not pose any additional risk.
The modifications to the Hand Drill do not increase the risks from the predicate Hand Drill.
The MRI Hand Drill is a safe alternative to power drills. It is still the case that the device operates at very low speed, and is manually powered. Both of these characteristics lead to a safe device in most cases. Most of the failures of the device occur toward the safe end-that is, the device does not spin or stops being usable, instead of failures that result in a loss of control. There were no new failure modes uncovered during testing that challenge the premise. In addition, most of the failure modes associated with the device are considered nonhazardous, as they do not result in any harm to the patient. The drill allows users to create small holes for interventional procedures in the MRI scanner. This is a great benefit to surgeons and patients, as it makes procedures faster and logistically easier. Therefore, the benefits of the device outweigh the risks.
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For the Drill Bit, there are also no new risks with the change to the shank geometry.
The Drill Bit had no material changes, so the highest severity items (FMEA-0064) remain unchanged:
Resistance Magnetic Force Displacement (RPN = 16, Severity = 8)
Drill made of non-biocompatible material (RPN = 80. Severity = 8) The change to the shank geometry does not add any new risks. As testing showed, it will only improve performance and allow users to exert less force to tighten the drill bit in the drill without slipping.
9. Consensus Standards:
The MRII Cranial Drill and accessories comply with the following recognized consensus standards:
- AAMI/ANSI/ISO 10993-1 Biological evaluation of medical devices Part ● 1: Evaluation and testing.
- . ANSI/AAMI/ISO 1135-1 Sterilization of health care - products - Ethylene oxide - Part 1: Requirements for development, validation, and routine control of sterilization process for medical devices
- ASTM F2052-05e1, Standard Test method for Measurement of ● Magnetically Induced Displacement Force on Medical Devcies in an MRI Environment.
10. Conclusion:
The modifications to the MRII Cranial Drill and 3.2mm Drill Kit were made in conformance with the company's design control procedures. Performance testing established the substantial equivalence of the modified MRII Cranial Drill and 3.2mm Drill Kit to the predicate MRII Cranial Drill and accessories, including design verification testing.
The MRII Cranial Drill has the same intended use and indications for use and similar technologies characteristics and principles of operation as the predicate Cranial Drill. The minor technological differences between the MRII Cranial Drill and accessories and its predicate raise no new issues of safety and effectiveness. Thus the modifications are substantially equivalent to the previously cleared MRII Cranial Drill and accessories.
§ 882.4300 Manual cranial drills, burrs, trephines, and their accessories
(a)
Identification. Manual cranial drills, burrs, trephines, and their accessories are bone cutting and drilling instruments that are used without a power source on a patient's skull.(b)
Classification. Class II (performance standards).